Imperial County, California, near the U.S./Mexico Border, is a low-income, primarily Latino community with a long history of cumulative exposures, including poor air quality. The county has consistently had one of the highest asthma hospitalization and emergency room visit rates in the state for school-aged children. The California Environmental Health Tracking Program- a program of the Centers for Disease Control and Prevention, the California Department of Public Health, and the Public Health Institute- are partnering with Comit Cvico Del Valle and the University of California, Berkeley to conduct a community-engaged project to reduce air pollutant exposures in this region and improve the health of its residents. The goals of the project are to: (1) Engage community members to define and map local hazards and assets to highlight factors contributing to cumulative exposures, community vulnerability and resilience; (2) Deploy a network of inexpensive real-time air monitors which will relay data to the internet for immediate information on pollution levels; (3) Use state of the art land use regression modeling to develop the most accurate and detailed picture possible of PM10, PM2.5, and NO2 exposures throughout the County for identification of hot spots near vulnerable populations; (4) Develop a public health action plan for reducing exposures, improving health, and ensuring project sustainability; and (5) Conduct an evaluation of the project, including partnership processes, community involvement in the research, and resulting public health actions. This project utilizes innovative approaches with the potential to provide sustainable public health benefits and ultimately serve as a model for community-engaged environmental health action. First, the project will augment traditional practices related to air quality monitoring by utilizing community expertise, priorities and direction to inform the placement of low cost air quality monitors. It will also develop novel methods to combine data from the low-cost monitors with existing data sources to create high spatial and temporal resolution maps of air pollution. Finally, the project will enhance a community-initiated online mapping tool with air quality data from the monitors. This project will ultimately build community capacity by developing skills related to asset/hazard mapping, air monitor site selection, and research and action related to hazards and environmental health.